Prepare all the vegetables: garlic, onion, potatoes, and cabbage. Set aside.
Heat the oil in a huge skillet and cook the spices until the mustard seeds pop, mixing constantly.
Add the garlic, onion and potatoes, and cook another 5-10 minutes.
Add the cabbage, mix, cover the pan and cook over slow-medium heat for another 25 minutes, stirring occasionally to make sure it doesn’t burn. (It might need a tiny bit of water to cook the potatoes well, but add only a tiny amount or the whole thing will be mushy).
Season with salt and pepper to taste.
Continue to cook until potatoes are cooked through.